The present invention relates generally to devices for repeatedly dispensing material and more specifically to an energy conserving dispensing device and method for dispensing material. In the past, various solid materials were utilized which sublimated, thereby dispersing a substitute odor for the odor found in public facilities. In order to enhance the dispersion of such sublimating materials, many suppliers developed powered fan devices which assisted in the dispersal of the sublimated material. Such devices are well known in the art. For example, the common assignee of the present invention owns U.S. Pat. No. 4,830,791 entitled Odor Control Device, issued May 16, 1989 which discloses a solid dispensing device. Also, odor control devices where a pressurized aerosol container is utilized are well known in the art. Aerosol-type dispensing devices typically include a battery powered motor that actuates the nozzle on the aerosol container on a periodic basis. Known devices have significant disadvantages. These devices do not inform the user of the amount of time or the number of days remaining until the container must be replaced or refilled. Additionally, such devices are not particularly energy efficient and if powered by batteries, require frequent servicing to replace the batteries.
It is also known to use liquid containers for dispensing odorizing liquid. Typically, a dispensing tube attached to the container directs a flow of liquid cleaning, disinfecting, or odorizing chemical (e.g. directly into a toilet bowl or the inside wall of a urinal). Such devices may also operate based on the flush action of a urinal or toilet and are referred to as in-line devices. One known device is a system for injecting metered amounts of chemicals into flush water as the flush water enters the toilet.
The above-described devices are usually battery powered to simplify installation. Because connection to a conventional AC outlet is not required for battery powered devices, installation is simplified and cost is reduced. When the batteries become depleted, the unit ceases to function. Accordingly, the batteries must be replaced periodically. Frequent replacement of the batteries is a significant disadvantage that becomes even more troublesome in devices that are not particularly energy efficient. Replacement of the batteries, if performed at unnecessarily frequent intervals, is an annoying task that increases maintenance costs and customer dissatisfaction. The problem of battery disposal also gives rise to environmental concerns. Customers are unwilling to perform frequent battery replacement and have been known to replace the entire device when battery replacement is required too frequently. Often, the device is replaced with an alternate model or a different manufacturer's device.
In any motorized device, a portion of the battery's energy is used during motor activation. In most devices described above that use a pressurized can or a liquid pump, a motor is coupled to the nozzle of the container through a gear and hammer arrangement. When the motor is activated, the nozzle of the container is depressed by the hammer resulting in dispensing of the odorizing material from the container. The motor is periodically activated for a predetermined period of time at predetermined intervals, causing a known power drain. It has been found that in these devices, the nozzle of the container is, at sometimes, depressed for a longer period of time than is necessary to activate dispensing. This is required to allow for a lower than optimal battery voltage level after some period of usage. In such systems, when the energy level of the battery is less than maximum, but still within operating parameters, nozzle depression occurs with less force and occurs more slowly, often resulting in dispensing of an inadequate amount of odorizing, disinfecting, or cleaning chemical. At very low battery levels, torque may be inadequate for the dispensing of any material.
To prevent this situation from occurring, the above-described devices are designed such that the motor causes the nozzle to be depressed for a predetermined period of time that is longer than necessary, such that a minimum amount of odorizing, cleaning, or disinfecting chemical will always be dispensed, even if the batteries are somewhat depleted. Accordingly, when the power level of the batteries is at a maximum, the motor continues to be energized even after the nozzle has been fully depressed and cannot be displaced any further. This is referred to as a motor stall condition because the motor is energized but the mechanical components cannot be further displaced, causing the motor to stop rotation.
Thus, during the dispensing cycle for known devices, especially when the batteries are at a full power level, the nozzle is fully depressed while the motor enters the stall condition. As described above, this guarantees that an adequate amount of odorizing, cleaning, or disinfecting chemical will be dispensed, even when the batteries are at a relatively low power level. Typically, the stall condition is terminated when a timer expires which deactivates the motor. However, applying power to the motor during a stall condition consumes a large portion of the stored power available from the batteries. The amount of power consumed during a motor stall condition is greater than the amount of power consumed during normal motor activation. This adversely affects the battery life and renders many of the above-described devices inadequate. To many consumers, the useful battery life of the dispensing device is the single most important factor in determining the acceptability and hence, the desirability of the device. Therefore, power efficiency is critical.
Additionally, a motor stall condition places excessive stress on the motor and on the gear arrangement used to convert motor motion into a nozzle-depressing motion. Excessive stress placed on the various mechanical components of the device may cause early component failure.
Accordingly, it is an object of the present invention to provide novel apparatus to substantially overcome the above-described problems.
It is another object of the present invention to provide a novel device for dispensing material that significantly reduces power consumption so that battery life is greatly increased.
It is a further object of the present invention to provide a novel device for dispensing material having a stall detection circuit to eliminate motor stall conditions.
It is also an object of the present invention to provide a novel device for dispensing material that eliminates motor stall conditions to greatly reduce the power drain on the batteries.
It is a further object of the present invention to provide a novel device for dispensing material having very low power requirements such that the batteries operating the dispensing device rarely need to be replaced.